Only 21% of the sulphate quota was used

The bioleaching process was effective, which enabled the discharge of sulphate-containing water fractions to the circulating leaching solution. Lower-than-average precipitation made it possible for the production process to operate for several months in a closed cycle, which meant that no discharge waters were released outside the industrial site. The total sulphate loading for the year was approximately one-fifth of the annual limit set in the permit.

Already in previous years, the amount of water stored in Terrafame’s mining site was successfully reduced to the target level of 1–3 million cubic metres, after which water management became part of normal operations with no increased risk level. The amount of purified water released from the site during 2018 totalled approximately 2.5 million cubic metres, which is approximately 2.8 million cubic metres less than in the previous year.

All the water discharged from the site was released north into the Oulujoki watercourse area and no water was discharged into the Vuoksi watercourse area in south. Most of the water was released via the discharge pipe in Lake Nuasjärvi. In May, approximately 0.12 million cubic metres of water was also released via Latosuo into the north-bound discharge route.

As in previous years, the substance concentrations of water discharged into water bodies were low and clearly below permit levels, apart from individual exceptions.
 

Concentrations of purified water released from the site in 2017–2018.
 

Based on confirmed analysis results, the sulphate loading resulting from purified water released from Terrafame’s site in 2018 was 3,434 tonnes, which accounted for approximately one-fifth (21%) of the maximum amount permitted in the environmental permit, which is 16,300 tonnes per year.
 

Sulphate load 2016–2018.
 

No significant exceptions in water management with effects outside the mining site occurred during the year. In the late summer and early autumn, in connection with the construction of the waste rock area, concentrations of metals exceeding the permit levels were found in the runoff due to the naturally occurring black schist in the bedrock. Due to runoff, metal concentrations were also high in Kivipuro, however, on account of low flow, the loading effect remained low. After the event, the water collection systems in the waste rock area were reinforced so that runoff could be directed to the water treatment process.

 

Loading on water bodies resulting from the operations

Discharge pipe

Loading
2018
Discharged
(m3)
Copper
(kg)
Manganese
(kg)
Nickel
(kg)
Zinc
(kg)
Sulphate
(t)
Sodium
(t)
Januar 25,146 0.0 70.0 0.3 0.4 76.1 17.5
February 8,125 0.0 22.0 0.2 0.2 22.2 5.4
March 105,856 0.1 232.9 2.6 3.3 222.3 42.3  
April 609,937 0.8 1,084.3 29.1 46.2 899.8 197.4  
May 608,305 1.1 374.4 23.8 40.4 575.6 98.5  
June 118,977 0.1 9.0 1.6 1.0 85.4 14.3  
July 298,297 0.3 74.9 4.1 4.6 503.6 77.8  
August 67,352 0.1 6.7 0.6 0.5 94.3 14.8  
September 257,712 0.4 14.0 2.3 1.3 417.4 61.8  
October 214,186 0.3 63.6 3.9 4.2 306.8 47.3  
November 40,415 0.1 21.7 1.0 1.3 54.6 8.4  
December 0.0 0.0 0.0 0.0 0.0 0.0 0.0  
Total 2,354,308 3.3 1,973.4 69.6 103.4 3,258.7 585.6
Permit limit (43/2015/1)   100,0 20,000.0 350.0 525.0 15,000.0 4,000.0
               

Water was not discharged from the industry site in December.

Old discharge routes

Loading
2018
Discharged
(m3)
Copper
(kg)
Manganese
(kg)
Nickel
(kg)
Zinc
(kg)
Sulphate
(t)
Sodium
(t)
South 0.0 0.0 0.0 0.0 0.0 0.0 0.0
North
(7 Mar–5 Apr)
120,975 0.1 130.2 3.1 4.0 175.4 33.2
Total 120,975 0.1 130.2 3.1 4.0 175.4 33.2
Permit limit (52/2013/1)   150.0 2,600.0 250.0 300.0 1,300.0 650.0
               

Total

Loading
2018
Discharged
(m3)
Copper
(kg)
Manganese
(kg)
Nickel
(kg)
Zinc
(kg)
Sulphate
(t)
Sodium
(t)
Discharge pipe and old routes 2,475,283 3.4 2,103.6 72.2 107.4 3,434.0 618.9  

Extensive monitoring was carried out in 2018

In official environmental monitoring, extensive monitoring was carried out in 2018, which included more biological monitoring than usual, for example. Depending on the topic, extensive monitoring is carried out every three or six years.

a On the basis of the monitoring results, the key environmental effects of the mine, such as noise, dust and vibration, have remained mainly unchanged. These effects are highest within the mining site and its immediate vicinity, but to some extent, effects have also been observed in real estate properties located closest to the mining site. However, the guideline values for noise and vibration were not exceeded in the measurements conducted on the properties.

A bioindicator study, carried out as a part of the extensive monitoring, showed effects of mining operations in the vicinity of production areas whereas outside the mining site effects were not observed. Ground water effects were still found in the immediate vicinity of the plant site, primary leaching area and the Kortelampi dam, which is located at Terrafame’s industrial site.

In surface water monitoring, the decrease in sulphate loading was seen in the receiving waterbodies as a decline in the water sulphate content. No water has been discharged in the direction of the Vuoksi watercourse area after the spring of 2016. The sulphate content of Lake Laakajärvi and the waterbodies below it has already decreased and is now very close to the content levels typical for the area. Lake Kivijärvi, which is located in the Vuoksi watercourse area, still has two stratified basins with elevated substance concentrations at the bottom. Lake Kivijärvi is nonetheless showing signs of recovery.

Lake Salminen and Lake Kalliojärvi in the Oulujoki watercourse area have remained stratified. There are signs of recovery in Lake Kalliojärvi. In Lake Kolmisoppi and Lake Jormasjärvi, the sulphate content has decreased to approximately one-quarter of what the content level was in 2013.

During the late winter months, before the seasonal overturn, the effect of purified waters was was observed in Lake Nuasjärvi as increased electrical conductivity and elevated concentrations of sulphate, manganese and sodium. As the loading was lower than in the previous year, the water sulphate content in Lake Nuasjärvi was also lower. The lake’s seasonal overturn extended to the entire mass of water during both the spring and autumn overturns, and discharge water did not prevent normal operation of the lake.

The primary leaching area’s groundwater is subject to enhanced monitoring

Terrafame has an extensive groundwater monitoring programme, the goal of which is to gain information on the surface level and quality of groundwater. There are 24 groundwater wells in the bedrock and eight in soil associated with the monitoring programme in the mining concession area. The monitoring also covers eight domestic water wells located in the areas surrounding the mining concession. In addition to these, the quality of groundwater is monitored in the catchment area of Lake Nuasjärvi from one domestic water well and the wells of two water intake plants. Based on the monitoring, the mining operations were not observed to have any impact on the quality or quantity of water in the domestic wells.

Based on the results of the monitoring, changes in the quality of groundwater due to industrial activities have been found in the immediate vicinity of the primary leaching area and the Kortelampi dam, which is located in the industrial site. The monitoring of groundwater impact was enhanced during the year. In the primary leaching area, improvements were made to the protective structures of the leaching solution collection system and new groundwater monitoring wells were taken into use in the so-called middle lane. A study on the groundwater impact of leaching areas and waste rock areas and the related preventive measures is underway, scheduled for completion by the end of February 2019. Enhanced monitoring will be continued until further notice.

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